Patent GB-704180-A (GB)
Title: Method and apparatus for making fibers from glass
Inventor: STALEGO CHARLES JOSEPH
IPC: C03B37/065
Filed: 1951-06-25
Abstract: 704,180. Forming glass fibres. OWENSCORNING FIBERGLAS CORPORATION. June 25, 1951, No. 15058/51. Class 56 Glass fibres are formed by feeding solid glass filaments crosswise into a high temperature high velocity blast immediately adjacent a restricted opening in a chamber in which a combustible mixture of gases is burned to form the blast, so that the advancing end of the filament is softened and attenuated by the blast, the filament being heated to a temperature approaching but below the softening temperature just prior to being fed into the blast. The preheating reduces the time required for the blast to melt the filaments so that the burner discharge opening may be more restricted to obtain an increased rate of attenuation, also the diameter and or rate of feeding the filaments may be increased without increasing the size of the fibres. Means may also be provided to cool the filaments just before they are fed into the blast so that their temperature may be controlled to give the required softening. As shown in Fig. 1, glass flowing in small streams from orifices 11 in a feeder 10 is attenuated to form filaments 12 by coacting rollers 13, 14, and these filaments are attenuated by the blast and deposited on a conveyer 16, a suction chamber 17 preferably being disposed behind the conveyer. The blast with a temperature of about 2900‹F. is formed by igniting a mixture of combustible gas and air fed at pressure, e.g. 1 to 5 pounds per square inch, in the burner 19. This burner comprises a refractory body 20 with a combustion chamber 21 terminating at one end in a perforated wall 22, and at the other end in a wall 28 with a restricted outlet 23. The body may have a sheet metal shell which forms an inlet chamber 25 to which the gas conduit 26 is connected. The relation of the cross-sectional areas of passage 23 and chamber 21 is suitably from 1 : 8 to 1: 4. The lining 20 at the front forms a socket 27 above the passage 23 with the part 29 of the front wall 28 formed of a heat resistant material which gives a very high heat radiation. The wall part 29 may be a separate member with rearward flanges 30, 31. The filaments 12 are directed by a guide 32 comprising a plate 33 with a plurality of spaced grooves 34 to receive the filaments and a cover 36. The plate 33 extends in juxtaposition to member 29 and terminates substantially flush with top wall 31 while cover 36 terminates short thereof as shown. The fibres advancing through the guide are heated by the wall portion 29 before they reach the blast. The lower end 35 of plate 33 may be cooled by a jacket 37 having inlet 38 and outlet 39 for a cooling medium. The burner and preheating apparatus 40 shown in Fig. 5 comprises a refractory body 41, metal casing 42, and two combustion chambers 43, 44 separated by a partition 45 and provided with outlets 47, 45. Chamber 43 terminates in a perforated wall 46 communicating with a chamber 49 which receives combustible gas from conduit 51, and this gas burns in chamber 43 to form the blast which discharges through the restricted outlet 47. Chamber 44 also receives gas through a similar wall 48, chamber 50 and conduit 52, but the combustion products are discharged through the outlet 45 which is not greatly restricted and so provide a soft flame which preheats the filaments 12. A plate 53 may be provided opposite the partition 45<SP>1</SP> to guide the filaments and prevent their deflection by blast from outlet 45. Plate 53 may be cooled through a jacket 54. The burner 50<SP>1</SP> shown in Fig. 7 is similar to burner 19 but has no pocket 27. The filaments are fed along a guide 521 comprising a plate 53<SP>1</SP> and cover 541, the plate 53'having grooves 53<SP>11</SP> and removable heat resistant tip 55, e.g. of platinum with grooves aligned with grooves 53<SP>11</SP> which terminates flush with the top of the blast opening 51<SP>1</SP>. The tip 55 is electrically insulated from plate 53<SP>1</SP> at 58 and is connected at its ends to an electric circuit, so that the current heats the tip and thence the filaments in contact therewith: The filaments are also exposed for heating by radiation from the burner walls. In the burner shown in Fig. 9 electrical resistance members 63, e.g. of graphite, are built into the burner 60 around the outlet 61 and heated by the passage of the current, and the top hot exposed through a recess 64 in the burner wall heats the filaments. A plurality of bars 63 also increase the velocity of the blast. The burner may have a sloping top wall 66 as in Fig. 10 and the filaments preheated by a small flame type burner 67 arranged between the burner 25 and guide 68. The front wall of the burner may be chamfered and the guide 72 correspondingly inclined as in Fig. 11, so that the filaments 12 are fed at an angle to the blast whereby a greater length of filament is subjected to the blast and the heating time thus increased. Other things being equal the angle of projection of the filaments into the blast determines the diameter of the final fibres, an increased angle giving finer fibres. Reference has been directed by the Comptroller to Specification 590,258.